Block-signal system.



A. G. DAVIS. BLOCK SIGNAL SYSTEM.

APPLIOATION FILED MAR. 28, 1906.

Patented July 6, 1909.

W/Z'nesses UNITED STATES PATENT OFFICE.

ALBERTYG. Davis, or SGHENECTADY, New YORK, assronoa T0 GENERALELECTRICcon- PANY, A CORPORATION or NEW YORK.

BLOCK-SIGNAL SYSTEM.

Specification of Letters Patent;

Patented .ru' e, 1m.

tems for electrically-operated roads employing the rails for the returnconductor for the power-current. Such roads have been installedheretofore with the'rails pro erly sectioned to i'ormblocks for thesigns -current, and with connections between the blocks adapted totransmit the power-current but so arranged as. to revent the flow of sialcurrent from one b ock to another. Suc an arrangement .is easilysecured for a single track, but it sometimes hap ens in the case ofroadshaving parallel trac ks that it is. desirable to cross-connect the twoor more tracks so as to improve theconductivity of the system for thepower-current. For instance, if the resistance of the rail-oircuit 'of ablock ishigh, owing to defectivebonding,

this will introduce a loss in the power-circuit if the tracks are notcross-connected, but with the cross-connections, the other tracks serveas a low-resistance shunt forthe defective rail-circuit. When suchcross-connectionsare employed, however, a difficulty 'is introduced inguarding against broken rails. Since the rails of one block are shuntedby the rails of the-parallel block or blocks, a

, broken rail will not open the signal-circuit,

and consequently, with a system as ordinarily arranged, thesignal for ablock may indicate clear. in spite of a broken rail in the block.danger, and the object of my invention is to reduce the possibility ofaccident from this 1 power-current, either thirdr'ails or trolley Therail ci-rcuit of the block A is supplied with alternating-current by atransfailure of current in either winding. Ob-i viously, if there is abreak in either rail, one of the twowindings' must be open-circuited;and by so arranging the signal apparatus that the signal is putat d'aner upon the failureof current in either win ing, absolute protec- Thisis obviously a source of fore in the case of direct-ourrentroads to em}ploy alternating-current for the si al-circuits, since by so doinginterference etween the power and signal-currents may readily beavoided.

My invention, as applied to roads having alternating-current si nalsystems, further comprises arranging the windings between thecross-connection from the other track to a the rails of the block, asvprimary transformer windings, and solarrangin the second trans formerwindings and the re ays supplied therefrom that the signal is putatdanger when eithegiprimary transformer winding, is deemerg1z Still morespecifically, my invention consists in vplacing both .primarytransformer arrangin the core that a 'portion'of it is traverse by analternating flux only upon an unbalanoing of the alternating signalcurviding a secondarywindin on that portion 'of the magnetic circuit wit1 means supplied from the secondary winding for putting the signal at;danger.

reference to the accompan' ing drawing,

which shows diagrammatlcal nal system arranged in accordhnce with myinvention. a

I have illustrated and shall describe my invention as applied to a roademploying alternating-current for the si a1 circuits, but it will beunderstood that-1n its broader altitrnkting-current system.

In the drawin A A represent the rails of road.

B B represent supply conductors for the netic member eopposite the threelimbs of the 'E-shapedmember, but separated from tion is secured. I Ithas been proposed heret o windings on the" same magnet, core, and sorent in the two. primary windings, and pro- My invention will best beunderstoodby a block Si l I raspect my invention is not limited to an 7two parallel bloc s of an electrically-operated across the rails and theprimary of which is connected to the alternating-current lme- 10scomprises an E-shaped member and a mageach of the limbs by an air-gap.Two coils F F are placed on the two outer limbs of the E-shaped memberand are connected in series across the rails A. These coils are so woundthat the alternating signal current passing through them produces a fluxwhich passes in series through the two coils and through the member e.With equal currents flowing through the two windings F the. middle limbof the E-shaped memberis not traversedby any alternating flux. Secondarywindingsf 7"are placed in inductive relation to the windings F F andsupply a coil G of the track relay. This relay is shown as of thetwo-phase induction type, since this form of relay is not affected by anunbalanced fluctuating power-current in the windings F F. The otherprimary coil H of the relay is supplied directly or through atransformer from the alternatingcurrent line-wires D.

-The short-circuited secondary member of the relay carries a contactwhich, when both prlmary relay cells are energized, closes a circuitthrough the source of current I and r the operating mechanism J of thesignal K. This 0 crating mechanism .is merely indicateddiagrammatically, and may be of any well-known type.

It will be seen that the point of connection between the two coils F Fis connected to the central point ofthe secondary winding of thetransformer supplyin the adjacent block of the same track, and a so tothe opposite track. This connection is made of sufficient cross-sectionto carry the power-current, as are also the transformer windingsconnected tothe track. The power-current coming from the adjacent blockof the same track, or from the opposite track, normally dividessubstantially equally between the coils F F, assing through the rails Ain parallel. T e magnetomotive forces due to this current in the coils FF oppose each other in the member e and assist each other in magnetizingthe central limb of the E-shaped member. The air-gaps between theE-shaped member and the'member e ar'efor the purpose of preventingsaturation of the core by the power-curren With a system as thus fardescribed, it will be seen that a break in one of the rails A, as, forinstance, at X, may not cause the signal K to indicate danger, sincecurrent will flow from the central point of the secondary of transformer0 through the cross-connection to the opposite block through thewindings F F in parallehthrough the rails A. in parallel, throu h thetwo portions of the secondary win 'ng of transformer C in oppositedirections, to the cross-connection,-

thence through the right-hand coil F and through the lower rail A to theright-hand terminal of the secondary of transformer. C. This current inthe winding F may be sufficient to energize the secondary winding f, and

'otl1er.relay,'the' contacts of which are normally closed, and areincluded in the signalo)erating mechanism. This signal is also s iown asof the polyphase induction type,- having a second winding N su pliedfrom the line-wires D, so that-fluctuatlons of the flux reduced bythepower-current in the central imb of themagnetic member E will notoperate the relay. -It will be seen that with current flowing throughonly one of the windings F, as, for instance, the right-hand winding, aswould be the case if a rail were broken atX, the alternating flux due tothe current in the right-hand winding F will divide between theleft-hand central limbs ofthe member E. This flux will consequentlyenergize the relay winding M so as to actuate the relay to open thesignal-circuit. This actuation of the relay will occur upon the deenerizing of either of the coils F, sp that a brea in either rail of theblock A will produce a danger indication of the signal.

I do not desire to limit myself to the particular construction andarrangement of parts here shown, but. aim in the appended claims tocover all modifications-w 1ch are within the scope of my invention.

'What I claim as new and desire to secure by Letters Patent of tlieUnited States, is:

1. In a signal system for electrically-operated roads having paralleltracks, a connec tion from a block to the parallel track adapted to forma path for the power-current, two windingsinserted respectively betweenthe rails of the block and said connection, a signal for said block, andmeans operative upon the failure of current in either winding forcausing said signal to indicate danger.

2. In a signal system for electrically-operated roads having paralleltracks, a comet:-

tion'from a block to the parallel trackadapted to form a path for thepower-current, two

windings inserted respectively between the rails of the block and saidconnection, a signal for said block, electric operating mechanismtherefor, and means operative upon the failure of current in'either ofsaid windings v for breaking the circuit of said operating mechanism.

3. ha signal system for electrically-operated roads having paralleltracks," a connection from a block to the parallel track adapted to forma path for thepower-current, two windings inserted respectively betweenthe rails of the block and said connection, a signal for said block,electric operating mechanism therefor, and relay contacts in'circuitwith ication with a broken rail in 70 break the circuit of saidoperatingmechanism upon winding.

4. In a signal system for electrically-operated roads having paralleltracks, means for supplying alternating-current to the rail circuit; ofa block, a connection from the block to the opposite track adapted toform a path forthe power current, two inductive windings insertedrespectively between the the failure of current in either rails of saidblock and said connection, a

signal for said block, and means operative upon the failure of currentin either of said windings for causing said signal to indicate danger. w

5. In a signal system for electrically-operated roads having paralleltracks, means for supplying alternating-current to the railcircuit of ablock, a connection from the block to the opposite track adapted to forma. path for the power-current, two primary transformer windings insertedrespectively between the rails of the block and said connection,secondary windings inductively re lated to said primary windings, relayssupplied from said secondary windings, and a signal controlled by saidrelays, said secondary windings and relays being arranged to causesaidsignal to indicate danger upon the failure of current in eitherprimary Winding.

6. In a signal system for electrically-operated roads having paralleltracks, means for supplying alternating-current to the railcircuit o l ablock, a connection from the block to the opposite track adapted to formI a path for the power-current, a magnetic circuit, two windings on saidmagnetic circult inserted respectively between the rails of the blockand said connection and arranged to produce a change of fluxdistribution in said magnetic circuit upon a failure of current ineither winding, a signal for the block, and means responsive to saidchange in flux distribution for causing the signal to indicate danger 7.In a signal system for electrically-opated roads having parallel tracks,means for supplying alternating-current to the rail-on cuit of a block,a connection from the block to the opposite track adapted to form a pathfor the power-current, a magnetic circuit, two windings on said magneticcircuit inserted respectively between the rails of the block and saidconnection and arranged to produce a change of flux distribution in saidmagnetic circuit upon a failure of current in either winding, secondary,windings on said magnetic circuit, relays supplied from said sec ondarywindings, and a signal for theblock controlled by said relays, saidsecondary windings and said rela s bein arranged tocause the signal toindicate f anger upon a path for the power-current, two windingsinserted respectively between the rails of the block and saidconnection, a magnetic circuit for said windings having a portiontraversed by an alternating flux only uponan unbalancing of thealternating-current" in said windings, a secondary winding carried onsaid portion of the magnetic circuit, a signal for the block, and meansfor causing said signal to indicate danger upon a how of current in saidsecondary winding.

9. In a signal system for electrically-operated roads having paralleltracks, means for supplying alternating-current to the rail circuit of ablock. a connection from the block to the opposite track adapted to forma path for the power-current, two windings inserted respectively betweenthe rails of the block and said connection, a magnetic circuit for saidwindings having a portion traversed by an alternating flux only upon anunbalancing of the alternating-current in said windings, a secondarywinding carried on said portion of the magnetic circuit, a signal forthe block, and a relay connected to said secondary winding andcontrolling said signal.

10. In a signal system for electrically-operated roads having paralleltracks, means for supplying alternating-current .to the rail-circuit ofa block, a connection from the block to the opposite track adapted toform a path for the power-current, two windings inserted respectivelybetween the rails of the block and said connection, a magnetic circuitfor said windings having a portion traversed by an alternating liux onlyupon an unbalancing of the alternating-current in said windings, asecondary winding carried on said portion of the magnetic circuit, asignal for the block, and a. relay coil connected to said secondarywinding and arranged when energized to cause said signal to indicatedanger,

11. In a signal system for electrically-operated roads having paralleltracks, a connection from a block to the opposite track adapted to forma path for the power-current, two windings mserted respectively betweenthe rails of the block and said connection, a magnetic circuit for saidwindings having a portion traversed by'a flux due to the current in saidwindings only upon an unbalancing of said current in said windings, asignal for the block, and means responsive to the flux in said portionfor causing the signal to indicate danger.

12. In an alternating-current signal system, a source ofalternating-current confor the block, and means for causing saidbalancing of the alternating-cui'rcnt in said nected to the rails of ablock, two windings connected in semes' across sald mlls, a signalsignal to indicate danger upon an unmezins for causing the sign-cl toindicatedanger upon an ,unlmlnncing ol' the altern: |.t111g c1n'|'c11t1n szud windings. E

14.'ln an ailtci'lmtmg-curl'cnt signal 'sys- 1 having two across saidran s, a mugnetlccu'cuit [or said term a source of alternating-currentconnected to the rails of a block, a transformer rlmzn'y windingsconnected windings \h aving a portion traversed by :L flux due to. thecurrent'in said windings only upon'sn'unbalancing of said current insaid windings, a signal for the block, and mezms responsive-to the fluxin said o1-tion for causing the signal to indicate dungel In witnesswhereof, I have hereunto set my hand this-26th day of Mural], 1906.

' AlJBlQWl (l. DAV 15. W itncsses BIGUJAMIN B. ll'uui, llnLnN ()l n onn.

